1. Field of the Invention
Developments in the state of the art relating to energy use and conservation systems have been directed in two areas: (1) development of energy conversion systems which are more efficient; and (2) development of energy conversion systems which, while likely to be less efficient, provide less costly methods of obtaining energy from less convenient power sources. It is in this latter area that the present invention is directed.
In many cases, the capitalization or maintenance costs make the use of relatively abundant or under-utilized energy sources uneconomical. For example, ordinary sewage is capable of producing a quantity of combustible gases, this production being added by heat resulting from the decomposition of the waste, However, the waste is usually fairly dilute and recovery of large concentrations of usable combustible materials is often uneconomical. Therefore, the development of energy from such a source is not considered to be economically attractive in a short-term sense. However, if a low-grade or dilute output of combustibles can be utilized, the production of energy from such waste composition sources can be economically attractive. There are, of course, numerous sources of small amounts of combustible materials, another example being evaporative losses from stationary storage of voluable fuel.
Additionally, there are numerous sources of low-level heat output, for example, industrial waste heat and even heat exhausted from chimneys of space heating apparatus.
In other cases, energy production is difficult because of the high cost of maintenance of a power plant. This is particularly true in remote locations where on-site access is difficult, as well as in under-developed countries with little or no service capabilities.
One field where maintenance costs are high are in the nuclear industry. In this case, maintenance costs are increased, not because of lack of technical expertise, but because of the difficulty in servicing radioactively-contaminated materials. For example, the placement of an engine physically adjacent to or within a nuclear pile becomes costly, not only because of the thermal problems involved, but because of the radioactive contamination of parts which need to be maintained.
The complexity, and the cost of producing and maintaining a power plant is closely related to the number of moving parts therein. Obviously, it would therefore be desirable to design an engine with as few moving parts as possible.
2. Description of the Prior Art
Sundry proposals have been made directed to simplified Rankine cycle and other heat engines. For example, U.S. Pat. Nos. 3,950,950; 4,009,576 and 4,070,862, all to Doerner and Van Burskik, disclose simplified rotary Rankine cycle engines. In these devices the condenser unit is caused to rotate, and the centrifugal force of rotation is used to control the movement of the working fluid. However, these engines use at least two separate rotary members in addition to the housing or stator member.
Andreas, U.S. Pat. No. 890,591, describes a rotary steam engine in which a disc rotating along with a working member functions as a centrifugal pump to drive the working fluid. However, Andreas does not disclose a rotary condensing chamber and, therefore, necessarily provides his centrifugal pump separately from his working blade space.
U.S. Pat. No. 1,790,196, to Bentley, shows a rotor member in a turbine which has grips or flanges provided thereon for the purpose of absorbing heat from exhaust steam and transferring the heat to within the rotor. However, the turbine described in this patent is of a non-condensing type and, therefore, centrifugal force developed by the rotation of the member could not be applied to pump the working fluid in its liquid form.
Numerous turbine designs make use of insulating coating on turbine materials, including U.S. Pat. Nos. 776,518 and 2,643,852. However, none of these patents discloses the coating of selected portions of turbine members for the purpose of providing separate heat conducting and heat insulating surfaces on a working member to which the working fluid is exposed.
While the prior art does not show a Rankine cycle engine in which all of the component parts are provided integrally with a stator and a unitary working member, the Stirling cycle engine does provide a unitary structure of the working member and the pump. However, the Stirling cycle engine requires a separate condensation means. Furthermore, the Stirling cycle engine has, thus far, not been as readily adapted to the use of a wide variety of fields because heat must be applied at the working chamber. Thus, the Stirling cycle engine provides a structure which is entirely different from even a simplified Rankine cycle engine.